Alzheimer's disease is the most common form of dementia occurring primarily in the elderly. It is a progressive neurodegenerative disease that affects over 3.1 million people in the US and 26.6 million people worldwide. Given the general aging of the population, the overall prevalence of Alzheimer's disease is expected to increase in the coming years. Researchers predict that global prevalence of Alzheimer's disease will quadruple by 2050 to more than 100 million.
Although not considered one of the core features of Alzheimer's disease and other dementias, neuropsychiatric symptoms are being increasingly recognized as important factors influencing the quality of life for patients and caregivers and may be the trigger for nursing home placement.
Most current treatments aimed at improving the cognitive dysfunction are based on the hypothesis that the cognitive deficits of Alzheimer's disease can be traced to loss of function in the cholinergic system in the CNS. Acetylcholinesterase inhibitors represent the mainstay of current Alzheimer's disease therapy, including donepezil (Aricept®), galantamine (Reminyl®), and rivastigmine (Exelon®). While these cholinergic-enhancing treatments produce some symptomatic improvement in some patients, therapeutic response has not been satisfactory for the majority of patients treated.
Dementia greatly affects quality of life for both patients and caregivers with Parkinson's disease as well. Safe and effective treatment options for dementia are much needed. Current treatments for Parkinson's disease dementia are mostly derived from those utilized in Alzheimer's disease. Rivastigmine, the only FDA-approved medication for Parkinson's disease dementia, is the first line treatment. However, more effective treatments are needed to help patients suffering from cognitive dysfunction. There thus remains a high unmet medical need for the treatment of neuropsychiatric symptoms, particularly of psychotic symptoms, and adverse cognitive effects due to Alzheimer's disease and/or Parkinson's disease.